CSS styles/layers help

 
 var isMinNS4 = (navigator.appName.indexOf("Netscape") >= 0 &&
 parseFloat(navigator.appVersion) >= 4) ? 1 : 0;
 var isMinIE4 = (document.all) ? 1 : 0;
 var isMinIE5 = (isMinIE4 && navigator.appVersion.indexOf("5.") >= 0) ? 1 : 0;
 
 
 
 function getWidth(layer) {
 
 if (isMinNS4) {
 if (layer.document.width)
 return layer.document.width;
 else
 return layer.clip.right - layer.clip.left;
 }
 if (isMinIE4) {
 if (layer.style.pixelWidth)
 return layer.style.pixelWidth;
 else
 return layer.clientWidth;
 }
 return -1;
 }
 
 function getHeight(layer) {
 
 if (isMinNS4) {
 if (layer.document.height)
 return layer.document.height;
 else
 return layer.clip.bottom - layer.clip.top;
 }
 if (isMinIE4) {
 if (layer.style.pixelHeight)
 return layer.style.pixelHeight;
 else
 return layer.clientHeight;
 }
 return -1;
 }